Inductively coupled plasma downstream strip module

ABSTRACT

A plasma processing module for processing a substrate includes a plasma containment chamber having a feed gas inlet port capable of allowing a feed gas to enter the plasma containment chamber of the plasma processing module during the processing of the substrate. An inductively coupled source is used to energize the feed gas and striking a plasma within the plasma containment chamber. The specific configuration of the inductively coupled source causes the plasma to be formed such that the plasma includes a primary dissociation zone within the plasma containment chamber. A secondary chamber is separated from the plasma containment chamber by a plasma containment plate. The secondary chamber includes a chuck and an exhaust port. The chuck is configured to support the substrate during the processing of the substrate and the exhaust port is connected to the secondary chamber such that the exhaust port allows gases to be removed from the secondary chamber during the processing of the substrate. A chamber interconnecting port interconnects the plasma containment chamber and the secondary chamber. The chamber interconnecting port allows gases from the plasma containment chamber to flow into the secondary chamber during the processing of the substrate. The chamber interconnecting port is positioned between the plasma containment chamber and the secondary chamber such that, when the substrate is positioned on the chuck in the secondary chamber, there is no substantial direct line-of-sight exposure of the substrate to the primary dissociation zone of the plasma formed within the plasma containment chamber.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to plasma processing modules forthe processing of a semiconductor substrate in the manufacture ofintegrated circuits. More particularly, the present invention relates todownstream, inductively coupled plasma processing modules and methods ofusing the modules during the processing of the semiconductor substrates.

[0002] Semiconductor substrates are typically processed using plasmaprocessing modules to perform various process steps during themanufacture of the semiconductor devices. Generally, theseplasma-enhanced processes are well known to those skilled in the art andinclude various etching processes and stripping processes.

[0003] In recent trends, plasma-enhanced processes have been morefrequently used to perform resist stripping. Traditionally, the resiststripping or ashing process has been considered a fairly straightforward process. However, due to the small feature size and increasedcomplexity of devices now common in the semiconductor industry,conventional plasma processing modules tend to cause plasma-induceddamage to the semiconductor devices during the processing of thesemiconductor substrates. To more thoroughly illustrate the problemsassociated with the use of conventional plasma processing modules, aprior art inductively coupled plasma processing module 100 will bedescribed with reference to FIG. 1.

[0004] As illustrated in FIG. 1, plasma processing module 100 includes aplasma chamber 102 formed by chamber walls 104 and dielectric window106. Plasma processing module 100 includes a feed gas inlet 108 forallowing feed gasses 109 to flow into chamber 102. An exhaust port 110is also provided for exhausting gases from chamber 102. An inductivesource 112, typically taking the form of a coil positioned on dielectricwindow 106, is used to energize feed gases 109 within chamber 102 andstrike a plasma within the chamber. In this example, inductive source112 is powered by RF power supply 114.

[0005] With the above described configuration, the shape of inductivesource 112 causes the plasma within chamber 102 to form a plasma havinga primary dissociation zone 116. This primary dissociation zone is theregion within the chamber that the plasma most efficiently dissociatesfeed gases 109 (for example O₂ and H₂O vapor) into neutral non-chargedspecies (for example O, H, and OH). In the case in which inductivesource 112 takes the form of a coil attached to dielectric window 106,primary dissociation zone 116 takes the form of a generally donut shapedregion located within chamber 102 directly below the coils of inductivesource 112.

[0006] Still referring to FIG. 1, plasma processing module 100 alsoincludes a liner 118, such as a quartz liner, for protecting the wallsof the plasma chamber from the plasma and reducing the recombination ofneutral radicals like 0 or OH. A chuck 120 is positioned in the bottomof chamber 102 and is configured to support a semiconductor substrate122. As is known in the art, chuck 120 may be heated to improve theefficiency of the process. Plasma processing module 100 also includes aquartz baffle 124 located above substrate 122. Baffle 124 includes aplurality of openings 126 formed through baffle 124 which cause anygases flowing through chamber 102 to be redistributed so that the gasesflow more evenly over substrate 122 than would be the case if baffle 124were not included in module 100.

[0007] Although baffle 124 partially shields substrate 122 from directexposure to the plasma, portions of substrate 122 remain directlyexposed to the plasma. This direct exposure to the substrate to theplasma may cause different types of the plasma-induced damage. Forexample, in semiconductor substrates having small feature sizes such as0.25 μm devices, charge damage can occur when electrically chargedspecies from the plasma accumulate non-uniformly on device gates andinterconnections. This charge accumulation can lead to large voltagepotentials across individual gates or between devices that can causegate degradation or loss of gate integrity. Device damage has been foundto correlate with the charge species dose that the device is exposed toduring the process. Therefore, exposing the device directly to chargedspecies produced within the plasma at high concentration (e.g.,>10¹¹/cm³) for even a short duration of time (e.g., seconds) or moderateconcentration (e.g., 10⁹/cm³ to 10¹⁰/cm³) for a longer duration (e.g.,tens of seconds) can cause significant problems for this type of device.In another example, device damage has been attributed to direct UVradiation exposure from the plasma. In the conventional configuration ofan inductively coupled plasma processing module, such as module 100described above, portions of substrate 122 are directly exposed to UVradiation from the plasma.

[0008] Another problem associated with conventional inductively coupledplasma processing modules such as module 100 is that they often providerelatively poor dissociation of the feed gases. In some cases, much ofthe RF energy is input into ionization at the expense of dissociation ofthe feed gas. This poor dissociation decreases the efficiency of andtherefore increases the time necessary for processing, furthercontributing to the above described problem of charge damage to deviceson the substrate. This poor dissociation is at least in part due to thefact that the feed gases 109 are not forced to flow directly through theprimary dissociation zones 116. As mentioned above, primary dissociationzones 116 are the regions within chamber 102 in which the plasma mostefficiently dissociates the feed gases.

[0009] The present invention provides improved designs for inductivelycoupled plasma processing modules and methods of using the novel modulesto process semiconductor substrates. These designs provide an isolatedplasma containment chamber within the module. This isolated plasmacontainment chamber prevents the semiconductor substrate from beingdirectly exposed to line-of-sight UV radiation produced by the plasmaand substantially reduces the concentration of charged species that thesemiconductor substrate is exposed to compared to prior art inductivelycoupled plasma processing modules. Also, the plasma processing modulesof the present invention provide a module that improves the dissociationof the feed gases compared to prior art inductively coupled plasmaprocessing modules. This is accomplished by specifically controlling theflow of gases through the module.

SUMMARY OF THE INVENTION

[0010] As will be described in more detail hereinafter, a plasmaprocessing module and methods of using the plasma processing module toprocess a substrate are herein disclosed. The plasma processing moduleof the present invention includes a plasma containment chamber having afeed gas inlet port capable of allowing a feed gas to enter the plasmacontainment chamber of the plasma processing module during theprocessing of the substrate. An inductively coupled source is used toenergize the feed gas and for striking a plasma within the plasmacontainment chamber. The specific configuration of the inductivelycoupled source causes the plasma to be formed such that the plasmaincludes a primary dissociation zone within the plasma containmentchamber. A secondary chamber is separated from the plasma containmentchamber by a plasma containment plate or shield. The secondary chamberincludes a chuck and an exhaust port. The chuck is configured to supportthe substrate during the processing of the substrate and the exhaustport is connected to the secondary chamber such that the exhaust portallows gases to be removed from the secondary chamber during theprocessing of the substrate. A chamber interconnecting portinterconnects the plasma containment chamber and the secondary chamber.The chamber interconnecting port allows gases from the plasmacontainment chamber to flow into the secondary chamber during theprocessing of the substrate. The chamber interconnecting port ispositioned between the plasma containment chamber and the secondarychamber such that, when the substrate is positioned on the chuck in thesecondary chamber, there is no substantial direct line-of-sight exposureof the substrate to the primary dissociation zone of the plasma formedin the plasma containment chamber.

[0011] In one embodiment, the feed gas inlet port and the chamberinterconnecting port are connected to the plasma containment chambersuch that the flow of any feed gases fed into the plasma containmentchamber through the feed gas inlet port is directed substantiallythrough the primary dissociation zone of the plasma within the plasmacontainment chamber. In another embodiment, the feed gas inlet port andthe chamber interconnecting port are connected to the plasma containmentchamber such that the flow of any feed gases fed into the plasmacontainment chamber through the feed gas inlet port is caused to passsubstantially through the primary dissociation zone of the plasma withinthe plasma containment chamber two times.

[0012] Preferably, the secondary chamber further includes a baffle platehaving a plurality of openings formed through the baffle plate. Thebaffle plate is positioned within the secondary chamber above thesubstrate such that the plurality of openings in the baffle plate causeany gases moving through the secondary chamber and out the exhaust portto flow over the substrate in a more uniformly distributed flow patterncompared to what the flow pattern would be without the baffle plate.Also, the plasma containment plate separating the plasma containmentchamber from the secondary chamber is preferably grounded.

[0013] In still another embodiment, the module further includes anadditional feed gas port. The additional feed gas port is positionedsuch that additional feed gases may be injected into the plasmaprocessing module without having the additional feed gases flow throughthe plasma containment chamber. In one version of this embodiment, theadditional feed gas port is connected to the secondary chamber such thatadditional feed gases may be injected into the secondary chamber withoutpassing through the plasma containment chamber.

[0014] In one embodiment, the plasma processing module includes an RFpower supply for powering the inductively coupled source of the module.Additionally, the module may further include a biasing arrangementconnected to the chuck in the secondary chamber. This biasingarrangement is configured to apply a bias capable of inducing a plasmawithin the secondary chamber. In one version of this embodiment, thebiasing arrangement is configured to apply a soft bias capable ofinducing a plasma having a plasma density of no more than about 10⁸ions/cm³. In one specific example, the biasing arrangement includes anRF power supply for applying the bias.

[0015] The various embodiments of the plasma processing module of thepresent invention may be used in a variety of methods of processing asubstrate within a plasma processing module. In one embodiment, asubstrate is placed within the secondary chamber of the processingmodule. A feed gas is then caused to be fed into the plasma containmentchamber through the feed gas inlet port. A plasma is energized withinthe plasma containment chamber using an inductively coupled source toenergize the feed gas within the plasma containment chamber. The gasesare drawn through the plasma processing module by exhausting the gasesfrom the secondary chamber through the exhaust port. These gases areused to perform certain processes on the substrate.

[0016] In one embodiment of a method of the invention, the process ofthe method is a stripping process for stripping a resist layer from thesubstrate. In one version of this method, the step of feeding a feed gasinto the plasma processing chamber includes the step of feeding O₂ andH₂O vapor into the plasma processing chamber.

[0017] In another embodiment of a method of the invention, a plasmaprocessing module that includes the biasing arrangement connected to thechuck in the secondary chamber is used. The plasma processing modulealso includes an additional feed gas port positioned such thatadditional feed gases may be injected into the plasma processing modulewithout having the additional feed gases flow through the plasmacontainment chamber. The process of this method is a stripping processfor stripping a resist layer and various residues from the substrate. Inthis embodiment, an additional fluorine containing feed gas is injectedinto the plasma processing module through the additional feed gas port.Also, a soft bias is applied to the chuck such that a plasma is inducedwithin the secondary chamber. In one version of this embodiment, a biasof between about 20-500 W, and preferably 20-200 W for a 200 mmsubstrate (about 0.6 to about 0.65 W/cm²) is applied thereby inducing aplasma having a plasma density of preferably no more than about 10⁸ions/cm³ and at most about 10⁹ ions/cm³.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The features of the present invention may best be understood byreference to the following description of the presently preferredembodiments together with the accompanying drawings.

[0019]FIG. 1 is a simplified cross-sectional view of a prior artinductively coupled plasma processing module.

[0020]FIG. 2A is a cross sectional view of a first embodiment of aninductively coupled plasma processing chamber designed in accordancewith the invention.

[0021]FIG. 2B is a cross sectional view of a second embodiment of aninductively coupled plasma processing chamber designed in accordancewith the invention.

[0022]FIG. 3 is a cross sectional view of a third embodiment of aninductively coupled plasma processing chamber designed in accordancewith the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] An invention is described herein for providing a downstream,inductively coupled plasma processing module and methods of using themodule during the processing of a semiconductor substrate. In thefollowing description, numerous specific details are set forth in orderto provide a thorough understanding of the present invention. However,it will be obvious to one skilled in the art that the present inventionmay be embodied in a wide variety of specific configurations. Also, wellknown plasma-enhanced processes and other processes associated with theproduction of integrated circuits on semiconductor substrates will notbe described in detail in order not to unnecessarily obscure the presentinvention.

[0024] Although the inventive plasma processing module will be describedas an inductively coupled plasma processing module using an inductivelycoupled RF transformer coupled source, the inventive module may bepowered using any inductively coupled source such as helicon or helicalresonators. These power sources, among others, are readily availablecommercially.

[0025]FIG. 2A illustrates a simplified schematic of a downstream,inductively coupled plasma processing module 200 designed in accordancewith the present invention. For illustrative purposes, like referencenumerals will be used throughout the various figures for likecomponents. Generally, module 200 is a module similar to module 100described above except that, in accordance with the invention, module200 includes a plasma containment chamber 202 and a secondary chamber204. That is, module 200 includes a plasma containment plate or shield206 that separates plasma containment chamber 202 from secondary chamber204.

[0026] In a manner similar to that described above in the background formodule 100, plasma containment chamber 202 and secondary chamber 204 areformed by chamber walls 104 and dielectric window 106. Plasma processingmodule 200 also includes feed gas inlet 108 for allowing feed gasses 109to flow into plasma containment chamber 202. Exhaust ports 110 are alsoprovided for exhausting gases from secondary chamber 204. Inductivesource 112, in this case taking the form of a coil positioned abovedielectric window 106, is used to energize feed gases 109 within plasmacontainment chamber 202 and strike a plasma within plasma containmentchamber 202. In this example, inductive source 112 is powered by RFpower supply 114 which takes the form of a transformer coupled source.Typical inductive source power ranges from about 250 W to about 5000 Wor more.

[0027] With the above described arrangement, the specific configurationand shape of inductive source 112 causes the plasma within plasmacontainment chamber 202 to form a plasma having primary dissociationzone 116. As described above, this primary dissociation zone is theregion within the chamber that the plasma most efficiently dissociatesfeed gases 109 into neutral non-charged species. In the case in whichinductive source 112 takes the form of a coil attached to dielectricwindow 106, primary dissociation zone 116 takes the form of a generallydonut shaped region located within plasma containment chamber 202directly below the coils of inductive source 112.

[0028] Plasma processing module 200 also includes liner 118 forprotecting the walls of plasma containment chamber 202 and secondarychamber 204 from corrosion or erosion and for reducing recombination ofreactive radicals. Liner 118 may be a quartz liner or any other suitableand readily available liner material capable of protecting the chamberwalls. Chuck 120 is positioned in the bottom of secondary chamber 204and is configured to support semiconductor substrate 122. As is known inthe art, chuck 120 may be heated to improve the efficiency of theprocess. As was described above for module 100 plasma processing module200 also includes quartz baffle 124 located above substrate 122. Baffle124 includes openings 126 formed through baffle 124 which cause anygases flowing through secondary chamber 204 to be redistributed so thatthe gases flow more evenly over substrate 122 than would be the case ifbaffle 124 were not included in module 200.

[0029] During plasma processing, the gas pressure within the plasmacontainment and secondary chambers may be from about 10 mT to about 10 Tor more, but typically the operating pressure is about 1 T. Feed gasflow may range from about 100 standard cubic centimeters per minute(sccm) to about 5,000 sccm or more for a 200 mm substrate.

[0030] In accordance with the invention, module 200 further includes achamber interconnecting port 208 that interconnects plasma containmentchamber 202 and the secondary chamber 204. Chamber interconnecting port208 allows gases from plasma containment chamber 202 to flow intosecondary chamber 204 during the processing of the substrate. Chamberinterconnecting port 208 is positioned between plasma containmentchamber 202 and secondary chamber 204 such that, when substrate 122 ispositioned on chuck 120 in the secondary chamber, there is preferably nosubstantial direct line-of-sight exposure of substrate 122 to theprimary dissociation zone 116 of the plasma formed within plasmacontainment chamber 202. If desired (but not required in all cases),chamber interconnecting port 208 may be positioned between plasmacontainment chamber 202 and secondary chamber 204 such that there is nopoint on substrate 122 that is in direct line-of sight with the primarydissociation zone 116 of the plasma formed within plasma containmentchamber 202.

[0031] Because chamber interconnecting port 208 is positioned betweenplasma containment chamber 202 and secondary chamber 204 such that nopoints on substrate 122 are in direct line-of-sight with the primarydissociation zone 116 when the substrate is positioned on chuck 120, themodule configuration of the invention substantially eliminates thepotential for damage to the substrate due to direct UV radiation. Moreimportantly, because primary dissociation zone 116 of the plasma issubstantially surrounded by the chamber walls of plasma containmentchamber 202, the vast majority of charged species formed within plasmacontainment chamber 202 collide with one of the walls. Thissubstantially reduces the concentration of charged species that are ableto pass through chamber interconnecting port 208 and into secondarychamber 204. This substantial reduction of the concentration of chargedspecies that are allowed to pass through chamber interconnecting port208 substantially reduces the dosage of charged species that substrate122 is exposed to. This reduces the chances of causing the charge damageto any devices on substrate 122 as described above in the background.

[0032] In one preferred embodiment, plasma containment plate 206 isgrounded as indicated by ground 210 in FIG. 2A. This grounding causescontainment plate 206 to attract any charged species and furtherencourages any charged species to collide with containment plate 206.This further prevents charged species from passing from plasmacontainment chamber 202 into secondary chamber 204.

[0033] In another aspect of the invention, feed gas inlet 108 andchamber interconnecting port 206 are connected to plasma containmentchamber 202 such that the flow of any feed gases 109 fed into the plasmacontainment chamber is directed substantially through primarydissociation zone 116 of the plasma within plasma containment chamber202. This is illustrated by arrows 212 in FIG. 2A. By placing feed gasinlet 108 and chamber interconnecting port 208 on substantially oppositesides of dissociation zone 116, this configuration improves theefficiency at which the fed gas is dissociated and reduces processingtime and/or reduces the damage to the substrate due to charged species.This configuration also helps prevent charged species from moving fromplasma containment chamber 202 into secondary chamber 204. Thisconfiguration also improves the efficiency at which the module producesthe desirable neutral species that are used for processing the substratecompared to prior art modules thereby improving the efficiency of theoverall module.

[0034] Referring now to FIG. 2B, several additional features that may beincluded in the novel module design will now be described with referenceto module 220 of FIG. 2B. Although FIG. 2A illustrates feed gas inlet208 as being multiple inlets located on the outer periphery of plasmacontainment chamber 202 and chamber interconnecting port 208 as beinglocated in the center of plasma containment plate 206, this is not arequirement. Instead, feed gas inlet 208 may be a single inlet locatedin the center of the top of plasma containment chamber 202 and chamberinterconnecting port 208 may be multiple ports located around theperiphery of plasma containment plate 206 as illustrated in FIG. 2B.This configuration causes feed gases 109 to substantially flow throughprimary dissociation zone 116 as illustrated by arrows 212 in FIG. 2Band in a manner similar to that described above for FIG. 2A. Althoughthis specific alternative is given, it should be understood that anyappropriate positioning of the feed gas inlet and the chamberinterconnecting port would equally fall within scope of the invention solong as their positioning prevents substrate 122 from having anysignificant direct line-of-site exposure to primary dissociation zone116 as described above.

[0035] As also illustrated in FIG. 2B, and in accordance with theinvention, plasma processing module 220 may further include anadditional feed gas port 222. The additional feed gas port is positionedsuch that additional feed gases may be injected into the plasmaprocessing module without having the additional feed gases flow throughthe plasma containment chamber. In the embodiment shown in FIG. 2B,additional feed gas ports 222 are connected to the secondary chambersuch that additional feed gases may be injected into the secondarychamber without passing through the plasma containment chamber.Injecting the secondary gas in this manner may be advantageous since thesecondary feed gas which may contain fluorine species is largelyseparated from the high ion concentration regions, which reducespotential erosion of the liner.

[0036] As described above, the plasma processing module includes an RFpower supply for powering the inductively coupled source of the module.Additionally, the module may further include a biasing arrangement 224connected to the chuck in the secondary chamber. This biasingarrangement is configured to apply a bias capable of inducing a plasmawithin the secondary chamber. In one version of this embodiment, thebiasing arrangement is configured to apply a soft bias capable ofinducing a plasma having a plasma density of no more than about 10⁸ions/cm³. In this specific example, the biasing arrangement includes anRF power supply 226 for applying the bias.

[0037] In another embodiment of a plasma processing module illustratedin FIG. 3 and indicated by reference numeral 300, feed gas inlet 108 andchamber interconnecting port 208 are connected to the plasma containmentchamber such that the flow of any feed gases 109 fed into plasmacontainment chamber 202 through feed gas inlet 108 is caused to passsubstantially through primary dissociation zone 116 of the plasma withinthe plasma containment chamber two times. This is illustrated by arrows302 in FIG. 3. In the embodiment shown, this is accomplished by shiftingplasma containment chamber 202 of the module over to one side of themodule. This allows feed gas inlet 108 to be positioned on one side ofplasma containment chamber 202 and chamber interconnecting port 208 tobe located on the opposite side of plasma containment chamber 202.

[0038] The above described positioning of inlet 108 and port 208 forcesany feed gas 109 fed into plasma containment chamber 202 to passsubstantially through primary dissociation zone 116 of the plasma twotimes as indicated by gas flow arrows 302. Because the feed gasses areforced to pass through the primary dissociation zone twice, thisconfiguration further improves the efficiency at which the moduledissociates the feed gas into neutral species rather than chargedspecies. Also, since chamber interconnecting port 208 now includes aright angle bend, this configuration insures that there is no directline-of sight exposure of the substrate to the primary dissociation zone116. Additionally, the chamber walls 104 that help form chamberinterconnecting port 208 may be grounded. This grounding of these wallsattracts any charged species causing them to collide with the wallthereby helping to prevent the charged species from flowing from theplasma containment chamber into the secondary chamber.

[0039] The various embodiments of the plasma processing module of thepresent invention may be used in a variety of methods of processing asubstrate within a plasma processing module. In one embodimentillustrated in FIG. 2A, substrate 122 is placed on chuck 120 withinsecondary chamber 204 of plasma processing module 200. Feed gas 109 isthen caused to be fed into the plasma containment chamber through feedgas inlet 108. A plasma is energized within plasma containment chamber202 using inductively coupled source 112 to energize feed gas 109 withinplasma containment chamber 202. The gases are drawn through the plasmaprocessing module by exhausting the gases from secondary chamber 204through exhaust ports 110. This is typically done using a vacuum pumpconnected to exhaust ports 110 as is known in the art. The gases movingthrough secondary chamber 204 are used to perform certain processes onsubstrate 122.

[0040] In the embodiment of the method of the invention currently beingdescribed, the process of the method is a stripping process forstripping a resist layer 310 from substrate 122. In one version of thismethod, oxygen and water vapor are fed into the plasma processingchamber as the feed gas. This feed gas is dissociated into variousspecies including O, H, OH, O⁺, O₂ ⁺, electrons, H⁺, and OH⁻. However,since the feed gas is forced to flow substantially through primarydissociation zone 116 as described above, a higher percentage of thefeed gas is dissociated into desirable neutral species (i.e. O) that maybe used to strip resist layer 310 from substrate 122.

[0041] In another embodiment of a method of the invention illustrated inFIG. 2B, plasma processing module 220, which includes biasingarrangement 224 connected to chuck 120 in secondary chamber 204, isused. Plasma processing module 220 also includes additional feed gasports 222 positioned such that additional feed gases 314 may be injectedinto plasma processing module 220 without having additional feed gases314 flow through plasma containment chamber 202. The process of thismethod is also a stripping process for stripping a resist layer asdescribed above. However, this process is also able to strip variousresidues, indicated by residues 312 in FIG. 2B, from substrate 122. Inthis embodiment, additional feed gas 314 is a fluorine containing feedgas that is injected into secondary chamber 204 through additional feedgas ports 222. Also, a soft bias is applied to chuck 120 using biasingarrangement 224 such that a plasma 316 is induced within secondarychamber 204. In one version of this embodiment, a bias of between about20-200 W is applied to chuck 120. This relatively soft bias inducesplasma 316 such that plasma 316 has a plasma density of no more thanabout 10⁸ ions/cm³.

[0042] Although the above described method has been described as using aspecific range of biasing that induces a specific plasma density, itshould be understood that this is not a requirement of the invention.Instead, as would be understood by those skilled in the art, the amountof bias applied and the plasma density may be varied to suit thespecific application.

[0043] The above described method of using additional feed gases andapplying a soft bias to induce a low density plasma provides a uniqueplasma processing method that is very useful in a wide variety of resistand residue stripping applications. For example, etching applicationswith features of 0.25 μm often require sidewall passivation chemistriesto maintain the required feature profile and critical dimensions. Intypical poly etch applications, for example, Cl₂ and HBr are used inconjunction with O₂ or N₂ additives. Sidewall residues which arecomposed of Si and one or more of Br, Cl, O, N, and C (from thephotoresist) are formed during the main and overetch processes. Thesesidewall residues must be removed before the substrate can be furtherprocessed. One possible alternative is to wet strip the residues.However, it would be advantageous to be able to remove these residuesduring a plasma strip process. This can be accomplished in someapplications by applying a soft and low power bias (20-200 W) during aremote inductively coupled plasma strip process as described above. Atypical resist stripping chemistry would be largely composed of O₂ witha dilute addition of fluorine containing species such as CF₄, C₂F₆, NF₃,or SF₆.

[0044] In oxide etch applications such as via etch, sidewall residuesformed during the main etch and overetch steps may also not besuccessfully removed during a plasma resist strip. These residuesassociated with vias are often referred to as “veils” and may containtitanium and/or aluminum compounds because the underlying layer in atypical via etch may be Ti/TiN (often used as an antireflective coatingon aluminum interconnections) or aluminum layers. During the overetchprocess, for example, material from the bottom of the via is sputteredonto the sidewalls which leads to the formation of the veils. Theseresidues are particularly difficult to remove even with fluorinatedchemistries. Hence, it can be advantageous to apply a soft bias (again20-100 W) to ensure that the via veils are removed during thephotoresist stripping process.

[0045] Depending upon the specific application, the soft bias may not beapplied at all in some resist strip processes. However, it may beapplied during a portion or all of other resist strip processes.Additionally, the remote inductively coupled plasma process of thepresent invention may be applied to photoresist stripping followingmetal (aluminum) etching. In this application, the primary concern iscorrosion protection where the goal is to remove the chlorine speciesfrom the metal lines prior to exposing them to the atmosphere. Chlorinepresent on the metal lines can form HCl when exposed to moist air.

[0046] Since the above described processes that utilize a bias appliedto the chuck generally use a soft bias, this general approach avoidscausing charge damage to the devices on the substrate. Device chargedamage has been found to correlate with charge species dose to thedevice. With the high density plasma being generated in a remote plasmacontainment chamber in this invention, the current dose to the deviceeven with the soft bias applied in the secondary chamber is low enoughto not cause device damage. This is because the plasma density inducedby the soft bias is typically less than 10⁸ ions/cm³.

[0047] Although only a few specific embodiments of a plasma processingmodule have been described in detail herein, it is to be understood thatthe present invention is not limited to these specific configurations.In fact, the invention would equally apply regardless of the specificconfiguration of the module so long as an the high density plasma formedin the plasma containment chamber is energized using an inductivelycoupled source and so long as the substrate located in the secondarychamber has no substantial line-of-sight exposure to the primarydissociation zone of the plasma in the plasma containment chamber.

[0048] Also, while only a few specific examples of methods of how aplasma processing module of the invention may be used to process asubstrate have been described in terms of several preferred embodiments,there are alterations, permutations, and equivalents which fall withinthe scope of this invention. It is therefore intended that the followingappended claims be interpreted as including all such alterations,permutations, and equivalents as fall within the true spirit and scopeof the present invention.

What is claimed is:
 1. A plasma processing module for processing a substrate, the plasma processing module comprising: a) a plasma containment chamber including a feed gas inlet port capable of allowing a feed gas to enter the plasma containment chamber of the plasma processing module during the processing of the substrate; b) an inductively coupled source capable of energizing the feed gas and striking a plasma within the plasma containment chamber, the specific configuration of the inductively coupled source causing the plasma to be formed such that the plasma includes a primary dissociation zone within the plasma containment chamber; c) a secondary chamber separated from the plasma containment chamber by a plasma containment plate, the secondary chamber including a chuck and an exhaust port, the chuck being configured to support the substrate during the processing of the substrate and the exhaust port being connected to the secondary chamber such that the exhaust port allows gases to be removed from the secondary chamber during the processing of the substrate; and d) a chamber interconnecting port that interconnects the plasma containment chamber and the secondary chamber, the chamber interconnecting port allowing gases from the plasma containment chamber to flow into the secondary chamber during the processing of the substrate, the chamber interconnecting port being positioned between the plasma containment chamber and the secondary chamber such that, when the substrate is positioned on the chuck in the secondary chamber, there is no substantial direct line-of-sight exposure of the substrate to the primary dissociation zone of the plasma formed within the plasma containment chamber.
 2. A plasma processing module according to claim 1 wherein the feed gas inlet port and the chamber interconnecting port are connected to the plasma containment chamber such that the flow of any feed gases fed into the plasma containment chamber through the feed gas inlet port is directed substantially through the primary dissociation zone of the plasma within the plasma containment chamber.
 3. A plasma processing module according to claim 1 wherein the feed gas inlet port and the chamber interconnecting port are connected to the plasma containment chamber such that the flow of any feed gases fed into the plasma containment chamber through the feed gas inlet port is caused to pass substantially through the primary dissociation zone of the plasma within the plasma containment chamber two times.
 4. A plasma processing module according to claim 1 wherein the secondary chamber further includes a baffle plate having a plurality of openings formed through the baffle plate, the baffle plate being positioned within the secondary chamber above the substrate such that the plurality of openings in the baffle plate cause any gases moving through the secondary chamber and out the exhaust port to flow over the substrate in a more uniformly distributed flow pattern compared to what the flow pattern would be without the baffle plate.
 5. A plasma processing module according to claim 1 wherein the plasma containment plate separating the plasma containment chamber from the secondary chamber is grounded.
 6. A plasma processing module according to claim 1 wherein the module further includes an additional feed gas port, the additional feed gas port being positioned such that additional feed gases may be injected into the plasma processing module without having the additional feed gases flow through the plasma containment chamber.
 7. A plasma processing module according to claim 6 wherein the additional feed gas port is connected to the secondary chamber such that additional feed gases may be injected into the secondary chamber without passing through the plasma containment chamber.
 8. A plasma processing module according to claim 1 wherein the module includes an RF power supply for powering the inductively coupled source.
 9. A plasma processing module according to claim 1 wherein the module includes a biasing arrangement connected to the chuck in the secondary chamber for applying a bias capable of inducing a plasma within the secondary chamber.
 10. A plasma processing module according to claim 9 wherein the biasing arrangement is configured to apply a soft bias capable of inducing a plasma having a plasma density of no more than about 10⁸ ions/cm³.
 11. A plasma processing module according to claim 9 wherein the biasing arrangement includes an RF power supply for applying the bias.
 12. A method of processing a substrate within a plasma processing module, the method comprising the steps of: a) providing a plasma processing module including i) a plasma containment chamber having a feed gas inlet port capable of allowing a feed gas to enter the plasma containment chamber of the plasma processing module during the processing of the substrate, ii) a secondary chamber, iii) a plasma containment plate separating the plasma containment chamber from the secondary chamber, and iv) a chamber interconnecting port that interconnects the plasma containment chamber and the secondary chamber allowing gases from the plasma containment chamber to flow into the secondary chamber during the processing of the substrate; b) placing a substrate within the secondary chamber, the secondary chamber including a chuck and an exhaust port, the chuck being configured to support the substrate during the processing of the substrate and the exhaust port being connected to the secondary chamber such that the exhaust port allows gases to be removed from the secondary chamber during the processing of the substrate; c) causing a feed gas to be fed into the plasma containment chamber through the feed gas inlet port; d) using an inductively coupled source to energize the feed gas within the plasma containment chamber and strike a plasma within the plasma containment chamber, the specific configuration of the inductively coupled source causing the plasma to be formed such that the plasma includes a primary dissociation zone within the plasma containment chamber; and e) exhausting gases from the secondary chamber through the exhaust port such that the feed gas is drawn from the plasma containment chamber through the chamber interconnecting port into the secondary chamber and out of the plasma processing module through the exhaust port, the chamber interconnecting port being positioned between the plasma containment chamber and the secondary chamber such that, when the substrate is positioned on the chuck in the secondary chamber, there is no substantial direct line-of-sight exposure of the substrate to the primary dissociation zone of the plasma formed within the plasma containment chamber.
 13. A method according to claim 12 wherein the process of the method is a stripping process for stripping a resist layer from the substrate.
 14. A method according to claim 13 wherein the step of feeding a feed gas into the plasma processing chamber includes the step of feeding at least one of O₂ and H₂O vapor into the plasma processing chamber.
 15. A method according to claim 12 wherein the feed gas inlet port and the chamber interconnecting port are connected to the plasma containment chamber such that the flow of any feed gases fed into the plasma containment chamber through the feed gas inlet port is directed substantially through the primary dissociation zone of the plasma within the plasma containment chamber.
 16. A method according to claim 12 wherein the feed gas inlet port and the chamber interconnecting port are connected to the plasma containment chamber such that the flow of any feed gases fed into the plasma containment chamber through the feed gas inlet port is caused to pass substantially through the primary dissociation zone of the plasma within the plasma containment chamber two times.
 17. A method according to claim 12 wherein the secondary chamber further includes a baffle plate having a plurality of openings formed through the baffle plate, the baffle plate being positioned within the secondary chamber above the substrate such that the plurality of openings in the baffle plate cause any gases moving through the secondary chamber and out the exhaust port to flow over the substrate in a more uniformly distributed flow pattern compared to what the flow pattern would be without the baffle plate.
 18. A method according to claim 12 wherein the method includes the step of grounding the plasma containment plate separating the plasma containment chamber from the secondary chamber.
 19. A method according to claim 12 wherein the plasma processing module further includes an additional feed gas port positioned such that additional feed gases may be injected into the plasma processing module without having the additional feed gases flow through the plasma containment chamber and wherein the method further includes the step of injecting an additional feed gas into the plasma processing module through the additional feed gas port.
 20. A method according to claim 19 wherein the additional feed gas port is connected to the secondary chamber such that the additional feed gases are injected into the secondary chamber without passing through the plasma containment chamber.
 21. A method according to claim 12 wherein the module includes an RF power supply for powering the inductively coupled source.
 22. A method according to claim 12 wherein the plasma processing module further includes a biasing arrangement connected to the chuck in the secondary chamber and wherein the method further includes the step of applying a bias to the biasing arrangement that is capable of inducing a plasma within the secondary chamber.
 23. A method according to claim 22 wherein the step of applying a bias to the biasing arrangement includes the step of applying a soft bias to the biasing arrangement thereby inducing a plasma having a plasma density of no more than about 10⁸ ions/cm³.
 24. A method according to claim 22 wherein the biasing arrangement includes an RF power supply for applying the bias.
 25. A method according to claim 22 wherein a) the process of the method is a stripping process for stripping a resist layer and various residues from the substrate, b) the plasma processing module further includes an additional feed gas port positioned such that additional feed gases may be injected into the plasma processing module without having the additional feed gases flow through the plasma containment chamber, and c) the method further includes the step of injecting an additional fluorine containing feed gas into the plasma processing module through the additional feed gas port. 